Tino Zottola guitar amp construction books

[Cephus]

@Cephus--
Question: what's type of output transformer is that? My MA1 has the same one; it's even smaller than most 3W AA3 OTs...looks like a line transformer. But it really sounds nice! ('course I've running it through a 4 ohm cab--maybe the cool sound is 'cause it's expecting a 8 ohm load...)

The OP transformer in my MA1 is one of the 3W surplus transformers that AES sells. It does seem small, but appears to work well. I'll be putting these little amps on a dummy load and scope soon and measure their actual power output.

RE: the amp itself--previous owner bought it from Ebay, couldn't fix the noisy fizzyness. First I moved the earth ground away from the initial filter cap ground connection.

Oh, and the original builder installed a death cap, for some reason (even though it has a modern 3-prong cord.) Wow, even other amps plugged into the same mains circuit were fizzy, thanks to that cap. Problem fixed.

I don't think the fizziness came from the ground, but it certainly could come from that cap!

Also, it's got the "scratchy pot" syndrome, both on the amp and on the guitar. Typically, no coupling cap before the first stage, and volume's on a different stage. Maybe a cold solder joint?

You might try squirting some Deoxit into the pot. In the case of the MA1, the input is fed through a 68K resistor to the grid (1 meg to ground) of the first half of the 12AX7. output of that stage is capacitive coupled to the volume control, which is then part of the grid bias as well as level to the second half 12AX7.

[gmoon]

The OP transformer in my MA1 is one of the 3W surplus transformers that AES sells. It does seem small, but appears to work well. I'll be putting these little amps on a dummy load and scope soon and measure their actual power output.

Thanks! So that little guy is a 2500 / 8 OT. Since I've been reflecting back a 1250 ohm input impedance (with the 4 ohm cab), it's probably not working as efficiently (bit of a surprise, given the decent output.) I'll try an 8 ohm load; really like the sound currently, though.

I'll try spraying the pots, maybe that'll help, thanks.

The pots are oddball--both pots have holes cut in the backs (~3/8 in.) Not a great idea in a dusty environ. I suspect there were switches, and rather than live with the "click" of an unconnected switch (or buy new pots), the builder yanked the switches out...or they are surplus pots.

[ahmadyuzamir]

Unavailable in Malaysia

Hey everyone,

There's a lot we dont get in this part of the world. That includes the Tony Zottola book. Anyone knows where I can download it? Wink...wink...

[GypsyDavey]

Does anyone who has built an AA4 amp from Tino's book or a similar design have audio from it that you could share? I found an output transformer from an old radio that I scrapped that would work perfect for one, but I would like to hear one before I tackle a build. I'm generally not that crazy about the sound from single-ended guitar amps. They sound great clean, but don't seem to have the harmonics of amps with more than one output tube when you crank them (IMHO). Thanks!